German company Rocket Factory Augsburg (RFA) testing their Helix 2.0 power pack at Esrange Space Center in Sweden. The series of tests saw the new power pack run at stable operations and at the physical limits of flow rates.  

Rocket Factory Augsburg, based in Germany, developed and tested their Helix engine – the first European engine to demonstrate staged combustion technology. This engine uses an oxygen-rich staged combustion engine cycle, where a small fraction of propellants is burned in a pre-burner to drive the turbine, and the resulting gases are fed into the main combustion chamber with the remaining propellants – getting every last drop of energy out of the propellant.  

In a staged combustion engine, a small amount of propellant is burned to produce hot gas that drives turbines. These turbines power pumps that push the propellants into the combustion chamber at high pressure. The more the pump can raise the pressure of the propellants, the lower the pressure in the tanks needs to be, enabling lighter designs but also the more efficient the engine the better the performance of the rocket. In rocket engine terminology, the pumps and the power pack “close the pressure cycle” – if the system cannot increase the pressure of the liquids as needed, the engine will not work.  

 
Rocket engines are designed and built to operate at the extremes of physics and engineering, burning propellant at incredible rates to propel rockets and escape the clutches of gravity. A typical orbital rocket stage will easily burn through 150 000 kg of propellant in a matter of minutes. Just getting the vast amount of liquid propellants to the combustion chamber at the flow necessary requires a high-powered system of itself: the power pack. 

A rocket engine’s power pack provides everything needed to deliver liquid propellants from the tanks to the combustion chamber – exactly the right amount of propellant (fuel and oxidiser) at the right temperature and the right pressure. 

Helix engines run on liquid oxygen and Rocket Propellant-1 fuel, so the power pack needs to pump oxygen at liquid temperatures below −218°C at enormous speeds and turn it into a gas.  

The power pack test was supported by ESA’s Future Launchers Preparatory Programme (FLPP) ‘Thrust!’ Initiative (Technologies for High-thrust Re-Usable Space Transportation), which accelerates the maturation and demonstration of high‑thrust staged‑combustion propulsion technologies in Europe, enabling future reusable launch systems and strengthening Europe’s competitive and autonomous access to space.  

Rocket Factory Augsburg is also one of the European Launcher Challengers selected by the European Space Agency.